Crowing Chicken

Yes it is amusing and shocking when you first hear a chicken crowe. The first time I heard it I thought someone had played a prank and put a cockerel in with our girls.
By now she crowes every morning and it is quite funny to see her winding herself up to do it.
She will jump/fly from a perch and land on a shelter we built for them. She is quite old and my husband has moved the perch closer to the shelter because she was only just managing to reach it. Once on top of the shelter she stands wide leged and beak open to take some big breaths, then look out she starts. After about ten crowes she does a very large poo  and then hops down for breakfast. We have had to explain to our neighbours that we have not got a cockerel and just recently she has taken to crowing in the coup, which is quieter and has got it all done with by the time she comes out.
She will not crowe during the day. It's as if she has to have a "gargle" first thing in the morning. Is your chicken old? Has she stopped laying like ours?